How do you plan your interplanetary transfers?

[Alephzorg]

Going from a planet to the next isn't always easy. And usually, the first question is "is it the right time to even try to transfer?".

So there are tutorials, plugins, websites and so on to help us.

But how do you do it?

[merendel]

Most of the time kerbal alarm clock to get close to the right transfer window. From there I just setup a manuver node with the aproximate dV requirements and tweek the timeing till the intercept is in the right ballpark. Depending on how nasty the inclination change is I may get close and stick a second node at the AN/DN to make sure a viable intercept will work before doing the transfer burn. That second node obviously will need a recalculation once the first burn is done but can give me a good idea of the total dV reqirement to get an intercept and make sure its close to what it should be or if I need to do further refinement on the departure.

[Jouni]

I have two main methods:

1. I use the Launch Window Planner to find the first good enough launch window, and set up a maneuver node for that transfer. With a bit of practice, the numbers can be adjusted for a transfer burn directly from a moon's SoI (a return from Laythe or Tylo is the most common example).
   
2. Sometimes I treat the transfer as a standard orbital rendezvous. The initial escape burn places my apoapsis/periapsis on the target's orbit, while matching the inclination as well as possible. Then, as I arrive to the point where the orbits touch, I adjust the other apsis so that I'll have an encounter after one more orbit.
   

[Kasuha]

Why is alexmoon's calculator missing in the list?

[rennsport27]

I used to use protractor, but as I picked up the pace in career mode, I started using alarm clock so I could hit every interplanetary window. So, that led to me just using alarm clock to figure out the general time and winging the transfer burn from there.

[SpenSpaceCorp]

I look at thehttp://ksp.olex.biz/ tool and eyeball it and burn with Jeb saying, "Yep, looks 'bout right!"

[Stormweaver]

I tend to eyeball the easier ones (eve, duna, sometimes jool) and for others I just have a ship in orbit that I can make a node from, get the transfer in the right place and then just see how far ahead/behind my target it'd be. and warp from there.

Can 'Educated guess' be a poll option?

[Chiboko]

I use maneuver nodes to work out the right direction then just burn. Duna is on the opposite side of Kerbol? We could wait for a sane alignment but lets just make a bigger rocket.

[LethalDose]

I made my own Excel spreadsheets for Kerbin -> Planet transfers. I think I'm going to collate them all into a database for ease of use and flexibility.

[regex]

Why is alexmoon's calculator missing in the list?

^ This, so much. One of the best planners out there.

[Feldynn]

So far I've yet to leave Kerbin's SoI even though I've got almost 300 hours in the game , last thing I was doing was gathering science from all over Minmus but it's been a while since I last properly sent out some missions. I've always thought about sending some stuff off to Duna but never seem to get around to it LOL.

[DoToH]

Why is alexmoon's calculator missing in the list?

The OP wants the "other" option to win ?

[Merinsan]

I printed out Lando's transfer window (spreadsheet?) and stuck it on my wall. Just look up at it and work out when to go.

[Red Iron Crown]

Why is alexmoon's calculator missing in the list?

That would be my pick, too. The most flexible of the web tools for IP transfer.

[cantab]

Yet another vote for Alexmoon's. Along with Precise Node, so I can just copy the numbers across. A few minor tweaks will correct for non-zero inclination of my Kerbin orbit, and help me fine-tune my periapsis at the target (though that's arguably better done with a mid-course correction).

However, I am somewhat conscious that I don't know how to work out an interplanetary transfer for myself. It's one of the few aspects of KSP I can't do "manually".

[DaPatman]

I use KAC for the transfer times, and http://ksp.olex.biz/ to work out where to put the maneuver node.

[r4pt0r]

i do a burn to escape kerbin SOI, then place a node on my resulting kerbol orbit and play with it/slide it around till i get a good intercept. sometimes it takes a year of timewarp to reach an easy intercept, but no prob for me.

[FITorion]

experience.

I look at the relative positions and use the maneuver nodes. I don't use any tools other than what's in the base game.

[Brotoro]

Kerbal Alarm Clock for me, please. As long as I have it installed to keep track of simultaneous missions, it's handy to use for transfer notifications as well.

[NoMrBond]

I've just been winging it

I should probably put a bit more thought into it

After finishing this space station perhaps

[RocketPilot573]

I have a piece of paper that has the transfer-angles for Jool, Duna and Eve drawn on it. I hold it up to the screen to find where the planets should be. I make it myself waaaaaay back in .17 by waiting until Kerbin was lined up with the target planet, rising my solar apo to the target planet's altitude, and then coasting to apo. Then I measured the angle between the ship and the planet to see how far off I was. Works every time.

For other planets I use http://alexmoon.github.io/ksp/, it has many more features than http://ksp.olex.biz/, such as taking eccentricity and inclination into account.

[The Destroyer]

VOID

yea

[Superfluous J]

I used to use Alexmoon's calculator and loved it. However someone (and I wish I'd noted who) pointed out a very cool way to get spot-on transfers for every simple transfer in-game and I think I'll be doing that from now on.

• Once you're in orbit around Kerbin (or whatever planet/moon), set up an eject maneuver node to JUST leave the SOI to Sun's SOI. Ideally within 1m/s of staying caught. Make it on the correct side (retrograde for going inward toward Sun, prograde for going outward away from Sun).
  
• The resultant Sun orbit will be just ahead or behind Kerbin's Sun orbit. Place a maneuver node on that projected orbit, and plan your burn to your target planet. Drag the node around and fix prograde/retrograde or whatever until you get an encounter.
  
• Delete the FIRST maneuver node, and the SECOND one will become a timer to about the right time to eject.
  
• Fast-forward to that maneuver node, but don't do it. Just delete it once you reach it.
  
• Plan a new Maneuver node to actually do the transfer, and then do it.
  
• Revel in the fact that you just did an in-game efficient transfer without using an external tool.
  

[Jarin]

By the seat of my pants. Punch out of Kerbin's SOI, then play with maneuver nodes. Typically means I spend months in orbit. Occasionally I feel bad for the kerbals I make live in tiny pods for sometimes years at a time, but... not often.

[Alephzorg]

Why is alexmoon's calculator missing in the list?

I just didn't think of including it because I never used it myself. My bad.

The OP wants the "other" option to win ?

I do not endorse or support any product and/or method.

I usually create a list of transfer windows alarms in Kerbal Alarm Clock and play with maneuver nodes when I get close to them to plan for my burns.

Before that, I had printed sheets of transfer angles based on data from http://ksp.olex.biz/

Edited May 13, 2014 by Alephzorg
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